Stable viscous hydrocarbon oil



Patented Dec. 2, 194i STABLE VISCOUS HYDROCARBON OIL William H. Bahlkaflammond, 11111., assignor to Standard Oil Company, Chicago, 11]., a corporation 01 Indiana No Drawing. Application June 20, 1938,

Serial No. 214,725

6 Claims.

This invention relates to improvements in stable mineral oils and more particularly to improvements in stable petroleum oils.

Many petroleum products, such as lubricating oils, electric insulating oils, turbine oils, spindle oils, medicinal oils and the like are refined by drastic chemical treatment and/or solvent extraction in order to meet certain specifications. It has been observed that such drastic treatment seriously impairs certain properties of the oils, and most seriously the property of resisting oxidation. Such drastically treated oils are susceptible to sludging, high acidity and/or possible peroxide development. Oils which are readily oxidized develop bad odors, high acidity and large amounts of oil insoluble oxidation products which result in poor demulsifying and insulating properties and render them unsuitable for their intended use.

Heretofore the oxidation of oils of this type has been inhibited to some extent by the addition thereto of from about 0.001% to about'll.25% of certain antioxidants such as the polyhydric phenols and the alkyl derivatives thereof, for exampie catechol, tertiary butyl catechol, cresol, pyrogallol, hydroquinol, and the like, and the hydroxy condensed poly ring compounds and their alkyl derivatives, such as beta-naphthol, octyl beta-naphthol, amyl beta-naphtha], lauryl beta-naphthol, alpha-naphtha], cetyl alphanaphthol, butyl alpha-naphthol, amyl alphanaphthol and other alkyl derivatives of alphaand beta-naphthols. phenyl alpha naphthylamine, diphenylamine and butyl para aminophenol have been used. Although these antioxidants are efiective to a degree, substantially complete inhibition is not obtained in many cases. For example, in some cases the inhibitor will retard sludging due to oxidation under the elevated temperatures employed but will have little if any effect in inhibiting acidity formation. v

It is the primary object of this invention to provide oils which are not susceptible to high acidity development, are less susceptible to sludging than prior art products, and do not have a high oxygen absorption. It is another object of this invention to provide petroleum oilswhich have increased oxidation stability, which do not develop high acidity during service, and which retain their good demulsibility and insulating properties. It is still another object of the pres-= ent invention to provide a method .of increasing the oxidation stability of petroleum oils.

I have discovered that the foregoing objects Other inhibitors such as troleum oils in combination with the hereinbefore mentioned antioxidants small amounts, preferably from about 0.001% to about 1.0%, of certain sulfurized materials; namely, sulfurized animal fats and fatty oils, sulfurized vegetable fats and fatty oils, and sulfurized fish oils, the esters of such sulfurized fatty oils and/or combinations thereof. More particularly, I prefer to employ sulfurized sperm oil. Other sulfurized materials which may be employed are sulfurized lard oil, sulfurized tallow, sulfurized oleic acid, sulfuriz hottonseed oil, sulfurized corn oil, sulfurized tyl oleate, and similar materials.

The effectiveness of the sulfurized sperm oil in inhibiting the formation of sludge in oils is demonstrated by the datapresented in Table I which show the results of Snyder life tests using 0.02% of sulfurized sperm oil in conjunction with 0.05% of another inhibitor, specifically, amyl betanaphthol. The Snyder life test is an index of the oxidation stability of an oil, and is conducted by maintaining about 500 cc. of the oil at a constant temperature of about 120 C. and once every 24 hours withdrawing a 10 cc. sample, cooling and centrifuging the same for the purpose of determining when sludge first appears. The life of the oil is the number of days the oil is maintained at 120 C. before visible sludge is formed. The Snyder life test is fully described in the A. S. T. M. Proceedings, volume 24, part I, page 638 (1924).

At the end of 35 days No. 3 in the above table contained only 0.018% sludge.

The effectiveness of sulfurized sperm oil in inhibiting the oxidation of petroleum oils is further demonstrated by the following tests: three other oil samples having the following compositions (A) base 011, (B) base oil-+0.05% amyl B-naphtho], (C) base oil+0.05%' amyl B-naphthol+ 0.02% sulfurized sperm oil were heated at about 284 F. while being exposed to the atmosphere. Samples were taken periodically and the color, acidity, and sludge determined. Th results of can be attained by adding to highly refined pethis test are tabulated in Table Table II Color (N. P. A.) Acidity Time before lst sludge Sample 90 hrs.

114 7 hrs.

66 hrs.

90 hrs.

Hours Less than 66 Less thanlilifi its-s The above data Show the marked inhibiting effect of the sulfurized sperm oil on color, acidity and sludge formation of highly refined oils. above test the control'oil was a highly refined transformer oil. It will be observed that although the amyl B-naphthol alone decreased the acidity it had little effect onthe color and sludge forma- I tion. ''Although I have described my invention in thereof as applied to transformer and turbine oils, they are not to be taken as limiting the scope of the invention. My invention may, be efiectively applied to other highly refined petroleum products such as spindle oils, medicinal oils and lubricating oils. v I claim: 1. The method of inhibiting the oxidation of highly refined viscous hydrocarbon oils which In the v connection with certain preferred embodiments comprises adding thereto, in combination, sul- I 2. The method of retarding the oxidation of highly refined viscous hydrocarbon oils which comprises adding thereto, in combination, suliurized sperm oil and amyl beta-naphthol, said addition agents being added in small but suifw cient quantities to adequately retard the oxidation of said highly refinedviscous hydrocarbon oils.

8. The method of inhibiting the oxidation of highly refined viscous hydrocarbon oils which comprises adding thereto from about 0.001% to about 1% of suliurized sperm oil and from about 0.001% to about 0.25% of amyl beta-naphthol.

4. An oxidation resistant highly refined viscous hydrocarbon oil containing from about 0.001% to about 1%ofsulfurized sperm oil and from about 0.001% to about 0.25% of amyl beta-naphthol.

5. An oxidation resistant viscous hydrocarbon oil comprising a highly refined viscous hydrocarbon oil normally susceptible to oxidation and. in

combination, in small but sumcient quantities to substantially inhibit the oxidation of said highly refined viscous hydrocarbon oil, sulfurized sperm oil and an organic compound having antioxidant properties selected from the class consisting of polyhydric phenols, alkyl polyhydric phenols, naphthols, and alkyl naphthols.

6. An oxidation resistant viscoushydrocarbon' oil comprising a highly refined viscous'hydrocarbon oil normally susceptible to oxidation and in combination,in small but sufllcient quantities to substantially inhibit the oxidation of said highly refined viscous hydrocarbon oil, sulfurized sperm oil and amyl 'beta-naphthol.

WILLIAM H. BAHLKE. 

